An electrical junction box is mounted in an engine room of an automobile, the junction box being for use in delivering electrical power from a battery to various electronic components. The electrical junction box includes a plurality of connectors and a main-body case and a cover that are each integrally resin-molded and configured to accommodate therein an electrical circuit board connected to the connectors.
In the electrical junction box, there is provided a locking projection protruding on an outer surface of either one of the main-body case and the cover. Also, there is provided an engagement projection protruding on an inner surface of the other one of the main-body case and the cover. By virtue of engagement of the locking projection with the engagement projection, the cover is attached to the main-body case so as to protect the electrical circuit board accommodated within the electrical junction box from external water droplets and dusts (see the patent literature 1).
In the electrical junction box with such a configuration, in some cases it is necessary to provide a stepwise portion on a peripheral wall of the main-body case in view of external dimensions of an ECU unit incorporated in the electrical junction box.
FIG. 7 schematically illustrates a conventional electrical junction box 1 having a stepwise portion of this kind, in which the electrical junction box 1 includes a main-body case 2 and a cover 4 that are integrally resin-molded. A locking projection 52 protrudes from an outer surface of a peripheral wall 51 of the main-body case 2. By virtue of engagement of the locking projection 52 with a not-shown engagement projection protruding from an inner surface of the peripheral wall 53 of the cover 4, the cover 4 is attached to the main-body case 2 so as to protect a not-shown electrical circuit board accommodated in the electrical junction box 1 from external water droplets and dusts.
A not-shown ECU unit is mounted in the main-body case 2 via a lateral side 54 thereof. A portion of the main-body case 2 is enlarged corresponding to an external dimension of the ECU unit. Specifically, a portion 51a of the peripheral wall 51 of the main-body case 2 has a stepwise portion 55 so that the ECU unit is mounted in an enlarged portion 56 of the main-body case 22 where the stepwise portion 55 is provided.